Plug for use in conduits



1953 L. J. HERNDON, JR., ETAL 3,100,534

PLUG FOR USE IN CONDUITS Filed May 31, 1980 INVENTORS. LUTHER J. HERNDO/V JR.

GEORGE w. EVANS 4% R. LAND 4; K Wu 0mm AGENT.

United States Patent Office Patented Aug. 13,- 1963 masses PLUG FUR USE IN CUNDUTTS Luther J. Herndon, 322, George W. Evans, and Eohn R. Land, Duncan, ()lda, assignors to I-Ialiiburton Com pany, a corporation of Delaware Filed May 31, 1960, filer. No. 32,657 4 Claims. (Q1. 166-153) This invention relates generally to plugs for preventing contamination between materials being moved through a conduit.

More specifically, it relates to a plug for preventing contamination between a well treating material and the material used to displace the treating material being pumped through tubing or casing to the desired location in the well.

Plugs or" various types have been in common use in the oil industry for many years, particularly in the cementing of wells. It is well known that some means must be provided to prevent the contamination of the treating material, i.e., cement slurries, by drilling fluids or connate waters. Contamination to any great degree during cementing operations will result in lower strength set cement and poor bonding to the well pipe.

Heretofore, because of the relatively shallow depth to which wells were drilled, it has been possible to obtain satisfactory separation of the treating material and the displacing material by the use of plugs, such as the type shown in US. Patent No. 2,257,784, issued October 7, 1941, to N. F. Brown.

Presently, however, due to the state of thewell drilling ant, well depths have increased until it is now common practice to drill to 10,000 feet or below and in many cases below 20,000 feet.

-It has been found that the plugs now in use have a tendency to wear to the point where an effective seal with the conduit is no longer attained. When the plug fails to seal, then the materials may pass thereby intermingling and contaminating the treating material. This condition is particularly true where the distance the plug is moved through the conduit exceeds 6,000 feet, and frequently occurs around 3,000 feet.

An object of the present invention is to provide an improved plug that obviates the prior art disadvantages.

Another object of this invention is to provide an improved plug that will maintain an effective seal with the conduit even when moved relatively long distances therethrough.

Broadly, this invention contemplates a plug for use in conduits having a resilient upper portion considerably larger than the interior diameter of the conduit and a lower portion adapted to guide or maintain the plug properly oriented as it moves through the conduit.

The foregoing and additional objects and advantages of the invention will become more apparent when the following description is read in conjunction with the accompanying drawing wherein similar numbers denote similar parts in all views and wherein:

FIGURE 1 is a view of a plug constructed in accordance with the invention shown partly in elevation and partly in cross section.

FIGURE 2 is a view of a plug constructed in accordance with another embodiment of the invention shown partly in elevation and partly in cross section.

Referring to the drawing in detail and first to FIGURE 1, there is therein shown a plug having a body 2 and an insert 3 located in the body 2.

The body 2 is constructed of a resilient material, such as rubber, neoprene, or any other similar material depending, among other things, upon the treating materials used. Neoprene, having a durometer reading of from intermediate portion 5 tapering downwardly and inwardly therefrom. The intermediate portion 5 may be described as a frustum of a cone having its larger base joining the spherical upper portion 4 and having adjoining outer surfaces tangent to the spherical surface of upper portion 4. A lower portion 6 includes an exterior guiding flange 7.

The insert 3 is formed from a relatively hard material, such as aluminum, steel or brass. In the preferred method of construction the insert 3 is permanently molded or vulcanized into the lower portion 6. The insert 3 may be threaded as at 9 so that auxiliary apparatus, such as a latching mechanism (not shown) may be attached thereto.

In the embodiment shown in FIGURE 1, the outer diameter of the spherical upper portion 4 is considerably larger than the interior diameter of a conduit in which theplug is to be used. The outer diameter of the flange 7 serves to maintain the plug in its upright position and does not necessarily form a seal with the conduit. However, to be certain that the guiding action takes place, it is preferred that the flange 7 be a slight interference fit with the inside of the conduit.

The embodiment hereinbefore described is admirably suited for use in conduits having a diameter of less than 5 /2 inches and although it may be used in largersizes, the larger solid plugs tend to become rather cumbersome. One embodiment of a larger size plug which may be used is illustrated in FIGURE 2. In this embodiment,

' the upper spherical portion 4a has an interior chamber 10 which is filled with a fluid, either gas or liquid, under pressure. The fluid thus confined provides the desired resiliency so that an effective seal may be maintained with the conduit. 7

In the embodiment of FIGURE 2, an intermediate portion 5a is provided, and although of somewhat different shape serves the same purpose as the intermediate portion 5 of the plug shown in FIGURE 1. A lower portion 6a includes an exterior guiding flange 7a similar to the flange 7 shown in FIGURE 1. Although 7 and 7a are shown as exterior flanges, they serve only to orient the plug and may be of any suitable configuration.

It should be pointed out that the insert 35, illustrated in FIGURE 1, may or may not be used depending upon the use for which the plug is intended. No insert is shown in FIGURE 2, but one may be provided if desired.

In operation, the plug is inserted in a conduit (not shown) between two materials that are to be kept separated. Upon entering the conduit, the flange '7 deforms slightly to provide the desired guiding action. The upper portion 4 or do is deformed since its diameter is larger than the inside diameter of the conduit thus providing both a seal with the conduit and a wiping action as the plug is moved therethrough. It is important to note that the resiliency of the material provided in the plug of FIGURE 1 and the compressed fluid of the plug of FIGURE 2 tend to continuously force the outer surface of the plug against the interior wall of the conduit, thus maintaining a seal with the conduit at all times. Further, it should be noted that a relatively large reservoir of resilient material is provided in the upper portion 4 and.

4a, tending to maintain the seal even though the material is Worn away as the plug passes through the conduit.

Sometimes it is desired to stop the plug at a particular position in the conduit. In accordance with well known principles, an interior flange (not shown) is placed in the conduit so that when the plug contacts the flange, its motion is arrested. However, if suflicient pressure were V v r 3,100,584

to be'applied, the plug could be pumped through the flange due to its resiliency. The plug when used in this manner should be provided with the insert 3 which will engage the flange and prevent the plug from passing therethrough.

It should be apparent that any number of the plugs may be used depending on the number of materials which are to be kept separated.

The embodiments shown and described herein are by way of example only andit should be understood that many modifications and variations may be made without departing from the spirit of the invention or the scope of the annexedclaims.

We claim:

1. A plug for use in segregating adjacent bodies of fluids in a conduit, said plug comprising an elongate resilient body having:

a guide portion;

a seal portion axially spaced from said guide portion and adapted to' be positioned above said guide portion when said plug is positioned within a conduit;

and a connecting portion disposed intermediate of and joining said guide and seal portions;

said guide portion including continuous, cylindrically configured, peripheral surface means coaxialwith the axis of said plug and having a diameter adapted to provide an interference fit with interior wall means of said conduit;

said seal portion including a substantially spherical segment coaxial with said plug axis and defining a closed end of said plug, said spherical segment being of substantially greater diameter than the diameter of said conduit interior wall, and peripherally engageable with said Wall; said spherical segment being axially elongatable whereby, in being radially constricted by peripheral engagement with said conduit interior wall means, said segment may resiliently expand axially of said plug; and said connecting portion being resilient, coaxial with said plug axis, integral with said seal and guide portions, and of less width than the diameter of said spherical segment. 2. A plug as defined in claim 1, also including an insert member in said guide portion, said insert member being formed of material of substantially greater hardness than said resilient body and including threaded fastening means whereby auxiliary apparatus may be attached to said plug.

3. A plug for use in segregating adjacent bodies of fluids in a conduit, said plug comprising an elongate resilient body having:

a guide portion;

a seal portion axially spaced from said guide portion and adapted to be positioned above said guide portion when said plug is positioned within a conduit;

and a connecting portion disposed intermediate of and joining said guide and seal portions;

said guide portion including continuous, cylindrically configured, peripheral surface means coaxial with the axis of said plug and having a diameter adapted to provide an interference fit with interior wall means of said conduit;

said seal portion including a substantially spherical segment coaxial with said plug axis and defining a closed end of said plug, said spherical segment being of substantially greater diameter than the diameter of said conduit interior wall, and peripherally engagea'ole with said well;

said spherical segment being axially elongatable whereby, in being radially constricted by peripheral engagement with said conduit interior wall means, said segment may resiliently expand axially of said plug;

and said connecting portion being resilient, coaxial with.

said plug axis, integral with said seal and guide portions, and of less width than the diameter of said spherical segment, said connecting portion further being generally frusto-conical in configuration and merging tangentially, at its enlarging end, with said spherical segment of said seal portion; said connecting portion and said seal portion comprising an integral, solid, resilient mass. 4. A'plug as defined in claim 1 wherein said resilient body seal portion includes in its interior a closed, fluid filled chamber.

References Cited in the file of this patent UNITED STATES PATENTS 1,122,246 Beam Dec. 29, 1914 2,257,784 Brown Oct. 7, 1941 2,370,833 Baker Mar. 6, 1945 2,567,475 Hall Sept. 11, 195.1 2,662,602 Schnitter Dec. 15, 1953 2,810,143 Reynolds Oct. 22, 1957 2,951,255 Ver Nooy Sept. 6, 1960 2,953,157 Osborne et al. Sept. 20, 1960 

1. A PLUG FOR USE IN SEGREGATING ADJACENT BODIES OF FLUIDS IN A CONDUIT, SAID PLUG COMPRISING AN ELONGATE RESILIENT BODY HAVING: A GUIDE PORTION; A SEAL PORTION AXIALLY SPACED FROM SAID GUIDE PORTION AND ADAPTED TO BE POSITIONED ABOVE SAID GUIDE PORTION WHEN SAID PLUG IS POSITIONED WITHIN A CONDUIT; AND A CONNECTING PORTION DISPOSED INTERMEDIATE OF AND JOINING SAID GUIDE AND SEAL PORTIONS; SAID GUIDE PORTION INCLUDING CONTINUOUS, CYLINDRICALLY CONFIGURED, PERIPHERAL SURFACE MEANS COAXIAL WITH THE AXIS OF SAID PLUG AND HAVING A DIAMETER ADAPTED TO PROVIDE AN INTERFERENCE FIT WITH INTERIOR WALL MEANS OF SAID CONDUIT; SAID SEAL PORTION INCLUDING A SUBSTANTIALLY SPEHERICAL SEGMENT COAXIAL WITH SAID PLUG AXIS AND DEFINING A CLOSED END OF SAID PLUG, SAID SPHERICAL SEGMENT BEING 